Michael Ojeda

Sorry guys if this is in the wrong section. I'm new here. This is something that has been giving me a bit of confusion. I haven't read any of the Forerunner saga books so forgive me if this has been answered but do Forerunners have 5 fingers or 6 on each hand? It is notable that the Didact had 6 fingers on each hand but the Librarian only had 5. Does anyone know the reason to this? Even in Halo on the level Sacred Icon, there was a terminal with 6 fingers on it. Does it vary per gender? I remember watching Halo legends and a forerunner put his hand on a terminal and he only seemed to have 5. Would love some clarification please